Page:Popular Science Monthly Volume 89.djvu/404

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390

��Popular Science Monthly

��it is woven back and forth arouiul wood- en pins set in a receptacle the size of a trunk, known as a "faking box." After this operation the box is turned upside down and the frame work hokling the pins is withdrawn, leaving the line ready to be "fed out," without becoming tangled. Prior to the insertion of the projectile in the gun, the first twenty or thirty feet of the line are dampened, so as to give it more elasticity and lessen the danger of its parting. A cartridge containing about ten ounces of black powder is inserted in the breech of the gun which is then aimed and fired.

After ha\"ing traveled about two hundred feet from the gun, the heavier end of the projectile causes it to turn in mid-air and assume the position of a comet with a long tail streaming behind it. Successful shots have been made with the three and six-pounders up to a distance of one thousand two hundred feet, and it is believed by t'oast Guard officers that further experiments with the guns will result in shots of two thousand feet and more.

The use of the rapid-fire guns for line shooting is something entirely new. For some time the Coast Guard has been utilizing shoulder guns for line shooting when a cutter can get to within 450 feet of a vessel in distress. The shoulder gun is another example of a gun designed to destroy but now used to save. The gun used for this purpose is the old 56-caliber Sharpe's carbine, the first breech-loading arm ex- tensively used by military forces in this country. Although of (obsolete type the weapon is well suited for line shooting and costs miu-li less than any other t> pi' of gun that could be provided for the purpose. The barrel is cut down to about fifteen inches in length and the breech block is constructed so as to receive a center- fire cartridge.

The projectile, shaped like that fired in (lie l)ig guns, is only about a foot long, and the largest

��end is alxjut a half inch in diameter. The line is also of a smaller size, and, instead of being held in a "faking box," is wound into a ball, which a sailor who stands beside the gunner holds in his hands. The line is wound in such a way as to allow it to "feed out" from the center of the ball. A regulation 56- caliber blank cartridge is used to fire the i^rojectile.

��Carpenter's Level, Compass, Grade- Finder and Periscope Combined A LEVEL and grade finder has been placed on the market which will not only give the exact distance out of the true level but will enable the operator to ascertain at one glance the true slant on any line or grade, either in degrees, inches or percentages or all at the same time.

It can be mounted on a tripod and used in all forms of grading, laying out roads, landscape gardening, placing of pipes for drainage, ascertaining fall of water, grade of hills for automobilists, cutting of rafters and laying off and leveling buildings.

A spirit le\el glass placed in the middle of the instrument can be seen from all sides if it is placed at an eleva- tion. By noticing the pointer on the dial it will give three guides for leveling. One of the most novel features of tht- instrument is an adaptation of the peri- scope principle in determining grades and their percentages.

���If Placed at Sufficient Elevation, a Spirit Level Glass in the Middle of the Instrument Can Be Seen from All Sides. The Pointing Hand Can Be Plainly Seen Through the Lens

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